The present invention relates to a light-emitting or light-receiving module equipped with a plurality of particle-shaped semiconductor devices and a method for making the same. This light-emitting or light-receiving semiconductor module can be used in various applications such as solar cell panels, illumination panels, displays, semiconductor photocatalysts, and the like.
Research has been done in technologies wherein a pn junction separated by a diffusion layer is formed on the surface of a small, spherical semiconductor element formed from p-type or n-type semiconductors. Multiple spherical semiconductor elements of this type are connected in parallel to a shared electrode to be used in solar cells and semiconductor photocatalyst.
U.S. Pat. No. 3,998,659 discloses an example of a solar cell. A p-type diffusion layer is formed on the surface of a n-type spherical semiconductor, and multiple spherical semiconductors of this type are connected to a shared electrode film (positive electrode) while the n-type cores of these spherical semiconductors are connected to a shared electrode film (negative electrode).
In U.S. Pat. No. 4,021,323, p-type spherical semiconductor elements and n-type spherical semiconductor elements are arranged in a matrix and connected to a shared electrode film. These semiconductor elements are also placed in contact with an electrolytic fluid. This results in a solar energy converter (semiconductor module) where electrolysis of the electrolyte takes place when illuminated with sunlight. U.S. Pat. Nos. 4,100,051 and 4,136,436 present similar solar energy converters.
In these types of conventional semiconductor modules, the semiconductor elements are connected in parallel. Thus, a low voltage and a high current is applied to the terminals of the module. If one of the semiconductor elements malfunctions and results in a short-circuit, a high current will pass through this short-circuit and output from the module will be lost.
As presented in PCT gazettes WO98/15983 and WO99/10935, the inventor of the present invention proposed a light-emitting or light-receiving semiconductor element wherein a diffusion layer, a pn junction, and a pair of electrodes are formed on a spherical semiconductor made from a p-type semiconductor and a n-type semiconductor. These multiple semiconductor elements of this type can be connected in series, and these series can be connected in parallel to form solar cells, photocatalyst devices involving the electrolysis of water and the like, as well as various types of light-emitting devices, color displays, and the like.
In these semiconductor modules, if any one of the elements connected in series malfunctions, an open circuit will result and current will not flow through the series circuit that includes the semiconductor element. As a result, the remaining operating semiconductor devices in the series circuit will also be stopped, lowering the output of the semiconductor module.
Furthermore, in the spherical semiconductor device with positive and negative electrodes proposed by the present inventor in the publications described above, the semiconductor device can roll around easily, making handling difficult. Determining the positions at which the positive and negative electrodes are formed is not easy and identifying polarity during assembly is difficult.